Khan.scratchpad.disable(); Christopher sells magazine subscriptions and earns $$8$ for every new subscriber he signs up. Christopher also earns a $$23$ weekly bonus regardless of how many magazine subscriptions he sells. If Christopher wants to earn at least $$88$ this week, what is the minimum number of subscriptions he needs to sell?
Solution: To solve this, let's set up an expression to show how much money Christopher will make. Amount earned this week $=$ $ $ Subscriptions sold $\times$ Price per subscription $+$ Weekly bonus Since Christopher wants to make at least $$88$ this week, we can turn this into an inequality. Amount earned this week $\geq $88$ Subscriptions sold $\times$ Price per subscription $+$ Weekly bonus $\geq $88$ We are solving for the number of subscriptions sold, so let subscriptions sold be represented by the variable $x$ We can now plug in: $x \cdot $8 + $23 \geq $88$ $ x \cdot $8 \geq $88 - $23 $ $ x \cdot $8 \geq $65 $ $x \geq \dfrac{65}{8} \approx 8.13$ Since Christopher cannot sell parts of subscriptions, we round $8.13$ up to $9$ Christopher must sell at least 9 subscriptions this week.